Cyclic positioning mechanism



April 29, 1969 E. a. BYAM ETAL 3,449,860

CYCLIC POSITIONING MECHANISM Sheet Filed July 18. 1966 IITVENTOR EvuumB. Bqam John C. MaMurvaq ATTORNEYS A ril 29, 1969 E. a. BYAM ETAL3,440,860

CYCLIC POSITIONING MECHANISM' Filed July 18. 1966 Sheet ,3 of s ET B.62m

6 l 6 la INVENTOR E'vuum B,Bu am John C. McMuvvaq D2 f0 0M8 WWWATTORNEYS United States Patent US. Cl. 72427 17 Claims ABSTRACT OF THEDISCLOSURE A mechanism for knocking a workpiece from a die by means of apin adapted to be inserted in the die carried on a frame member where afirst lever is pivotally mounted with respect to the frame and arrangedto advance the pin into the die. A second lever is pivotal with respectto the frame and is operated upon by a drive means for pivoting thesecond lever and a third lever is pivoted to the frame and is in contactat opposite ends thereof with the first and second levers so that uponpivotal motion of the second lever the third lever moves said firstlever to advance the knock-out pin.

This invention relates to positioning mechanisms arranged to cyclicallyoperate on a positionable member and more particularly relates to suchmechanisms which {nay operate at relatively high speeds with reducedbackash.

Linkage mechanisms embodying the invention may be incorporated in manytypes of machines which cyclically operate to position a member whichmay be reciprocably moved in a guide means. An example of such member isthe knock-out pin of a heading machine and the invention will bedisclosed in such environment.

Heading machines, well known in the art, generally comprise a die memberadapted to receive a workpiece in a die cavity, a gate carrying one ormore punches adapted to form a portion of the workpiece, a knock-outmechanism arranged to knock the workpiece from the die cavity after aforming blow upon the workpiece and a transfer mechanism adapted toposition a subsequent workpiece in or adjacent the die cavity prior to asubsequent stroke of the forming punch. The various mentionedmechanisms, the knock-out mechanisms, transfer mechanism and punchcarrying gate are all operated in timed relation to effect a cycle ofworkpiece heading, knock-out and transfer. Such timing of the variousmechanism is achieved through various elements, such as cams, connectingrods, levers, etc. As the speed of operation of a heading cycleincreases to correspondingly decrease the time in each heading cycle,the backlash or clearance between the various mechanical components mustbe minimized or eliminated to decrease non-working time and, further, todecrease the impact and acceleration loads on the various parts whichusually increase with increased speed of operation.

The present invention provides a new and improved mechanism which may beutilized as a knock-out assembly for a heading machine and whichdecreases the clearance or backlash between the operating parts thereofto enable higher speed operation without undue loading due to impact andacceleration on the parts, and which further reduces the noise levelduring operation due to the decreased backlash.

Accordingly, an object of this invention is to provide a new andimproved motion transmitting mechanism having greatly reduced backlash.

Another object of this invention is to provide a new and improvedknock-out assembly for a heading machine.

Another object of the invention is to provide a new and improvedknock-out assembly for a heading machine which contributes to higherspeed operation of the heading machine by reducing the backlash andclearance be tween the parts of the knock-out mechanism.

A further object of this invention is to provide a new and improvedknock-out assembly for a heading machine which eliminates backlashtherein when a knockout cycle is initiated.

A still further object of this invention is to provide a new andimproved knock-out assembly for a heading machine which is easilyadjustable to accommodate various size workpieces formed by the machineand the distance of the knock-out stroke without introducing backlashinto the system.

These and other objects of the invention are achieved in one formthereof through the utilization of a biased lever which is actuated intimed relation of movement of the machine punches through a drive leverand rocker lever in such a manner that once operation of the drive leveris initiated no clearance or backlash exists in the system. Morespecifically, this is achieved through an arrangement wherein aknock-out lever and a drive lever have a motion transmitted therebetweenby a rocker lever pivoted intermediate its ends which bear on both theknock-out lever and the drive lever. This arrangement is furtheradjustable to accommodate workpieces of various sizes and allowadjustment of the stroke of the knockout pin in accordance with the sizeof the workpiece.

The features of the invention which are believed to be novel are setforth with particularity and distinctly claimed in the concludingportion of this specification. However, the invention both as to itsorganization and operation together with further objects and advantagesthereof may best be appreciated by reference to the following detaileddescription taken in conjunction with the drawings, in which:

FIG. 1 is an elevation of a heading apparatus embodying the invention;

FIG. 2 is an end view of the apparatus of FIG. I seen from the righthand side thereof;

FIG. 3 is a view, partially cut away, seen in the plane of line 33 ofFIG. 2, and showing the knock-out assembly in a knock-out position;

FIG. 4 is a view similar to FIG. 3 showing the knockout assembly in arelaxed position; and

FIG. 5 is a view of another lever system embodying the invention.

A heading apparatus in which the invention may be embodied is generallyrepresented by the reference numeral 10 and comprises a base 11 havingthe frame 12 of the header mounted thereto. The apparatus includes amovable gate G carrying one or more punches arranged to act upon aworkpiece in a die 62. A set of cams 13 and 14 which operate a workpieceknock-out assembly are mounted to a shaft 15 rotatably mounted to frame12 by means of brackets 16. Shaft 15 is rotated in timed relation withthe operation of the machine parts such as the punches, etc., in amanner well known to those skilled in the art. Cams 13 and 14 operateupon cam followers 17 and 18 rotatably mounted to a three-arm crank 19which, in turn, is pivotally connected at 20 to a rod 21. When shaft 15is rotated, cam 13 acts on follower 17 to pivot lever 19counterclockwise about point 22 which extends rod 21 to the right, asviewed in FIG. 1. As cam 14 during the alternate portion of the cycleacts on cam follower 18, lever 19 is pivoted clockwise and retracts rod21. As will hereinafter be explained, When rod 21 is retracted under theoperation of cam 14, the knockout assembly is operated to knock-out aworkpiece from a die. When lever 19 is under the operation of cam 13,rod 21 is extended, and the knock-out assembly is turned to a relaxedposition.

The apparatus further comprises a drive pulley 23 mounted to a shaft 24which is driven by a prime mover such as an electric motor, not shown,and all parts, including shaft 15, are operated in synchronism or timedrelation to rotation of pulley 23 by means of suitable connectingdevices.

Hereinafter the cams 13 and 14 will be referred to merely as a knock-outcam whose function is to rock a crank 26 having arms 27 and 28 in fixedrelation to each other on a shaft 29 carried by frame 12. The free endof arm 28 carries an adjustable link 30, as will hereinafter beexplained.

Each of the arms 27 and 28 is connected to sleeve portions 32 and 33disposed about shaft 29 and joined to each other by means of a bolt at34. Rod 21 is pivotally connected to one end of arm 27 by a pin 35.

As more clearly shown in FIG. 3, link 30 may comprise a threaded shaft36 received in the end of arm 28 and carrying at one end thereof acamming member 37 which acts against a nose 38 of a drive lever 39pivoted to a shaft 40 carried by frame 12. Also pivotally mounted aboutshaft 40 is a knock-out lever 41, having a nose portion 42.

In accordance with one aspect of the invention, means are provided whichmay be adjusted to keep the backlash in the overall knock-out system toa minimum. This is highly desirable in high speed knock-out mechanisms,not only from the noise level but from the reduction of impact andacceleration load on the parts of the knock-out assembly.

A plate-like member 43 is mounted to frame 12 as by means of bolts 44and 45 and includes an elongated guide slot 46 therein which guidablyreceives a travelling member 47. Member 47 threadably engages a threadedshaft member 48 carried by member 43 so that upon rotation of shaft 48member 47 will move axially along shaft 48 Within slot 46. Whenpositioned along the length of shaft 48 member 47 may be locked to platemember 43 by means of nut 49 threaded to a stud portion 50 of member 47.Member 47 further carries a pivot-providing block member 51 which mountsa shaft 52. Pivotally mounted to shaft 52 is a rocker crank 53 havingnose portions 54 and 55 arranged to engage drive lever 39 and knock-outlever 41 on either side of shaft 40.

By means of the mechanism just described, the position of shaft 52 maybe varied along the length of shaft 48 within the confines of slot 46.

An abutment stop for lever 41 is provided in the form of a bolt 56threadably received in a nut-like member 57 in a bracket 57a on frame12. Bolt 56 is locked in position by a lock nut 58. The end 59 of bolt56 provides a stopping surface for knock-out lever 41 when it is rotatedin the clockwise direction, and the position of bolt 56 in member 57determines the limits of counterclockwise motion of knock-out lever 41.

In operation, when the knock-out cam retracts rod 21 crank 26 moves link30 forward to engage drive lever 39 which is pivoted in acounter-clockwise direction and engages nose 54 of rocker 53 which isalso pivoted in a counter-clockwise direction. Nose 55 of rocker 53 thenengages knock-out lever 41 which is also pivoted in a counter-clockwisedirection to the position shown in FIG. 3.

Nose 42 of knock-out lever 41 then engages and advances a plunger 60 inframe 12 to, in turn, advance a knock-out pin 61 in die 62 and knock-outa workpiece therein.

Movement of knock-out lever 41 to the position shown in FIG. 3 furtheradvances a plunger 63 against the bias of a spring 64 so that when rod21 is extended and link 30 withdrawn from drive lever 39, the energystored in spring 64 will move knock-out lever 41 to itsrelaxed positionas shown in FIG. 4.

In FIG. 4 the knock-out assembly is shown in the relaxed or retractedposition, and further illustrates the range of backlash or clearanceadjustment which may be achieved through the provision of rocker 53. Asthe member 47 is adjusted to the right (as shown in FIG. 4) the travelof knock-out lever 41 between a retracted position and a knock-outposition is decreased.

This mechanism provides a very high degree of repeatability to a fixedpoint which is exemplified as the set position of plunger 60 (FIG. 3).Upon adjustment of the system for a predetermined stroke of lever 41,during cyclic operation of the lever system, lever 41 and, morespecifically, contacting nose 42 thereof will always return to thisfixed point at the end of the knock-out stroke. This is accomplished bypredetermining the relationship of levers 39 and 41 so that in the fullknock-out position the lever 41 is set to a point to which it alwaysreturns at the end of a knock-out stroke. This alleviates the problemspresented by over or under travel of a knock-out lever and reduces wear,chatter and backlash of the parts.

In order to adjust the knock-out stroke two parameters must beconsidered, the length of the workpiece to be knocked out of die 62, andthe stroke of the knock-out lever. This adjustment is made by firstsetting the knockout lever 41 in the full knock-out position (as shownin FIG. 3) or spaced therefrom with a predetrmind minimum clearance.Lever 39 is then positioned in alignment with lever 41 to establish arelationship of the levers 39 and 41 that will always bring lever 41back to its set position when lever 39 is actuated. Member 37 is thenlocated at nose 38 on lever 39 or with predetermined minimum clearancewith respect thereto. At this time the edges of levers 39 and 41 incontact with rocker lever 53 are in a straight line relationship or,otherwise stated, reside in a common plane in parallel relationship. Inthis relationship member 37 is located to set knock-out pin 61 at theface 62a of die 62 or, alternatively, the shoulder 61a of pin 61 is inengagement with die 62. With drive lever 39 and knock-out lever 41aligned at the full knock-out position, the position of link 30 andmember 37 will remain constant within the limit of manufacturingtolerances. Next, link 30 through rod 21 is brought to the low positionon the knock-out cam, as exemplified in FIG. 4, so that it is backedoil? from drive lever 39. Holding spring 64 will now return knock-outlever 41 towards knock-out stop and abutment surface 59. A measuredlength of stock equivalent to that of a workpiece is inserted in die 62against knock-out pin 61 and the knock-out stop bolt 56 is adjusteduntil it just touches knock-out lever 41. Nut 49 is then loosened andscrew shaft 48 is turned to move member 47 and, more specifically,rocker lever 53 to a position to contact both knock-out lever 41 anddrive lever 39, with knock-out lever 41 held against the stop.

Now, in operation, when member 37 is advanced and contacts drive lever39, drive lever 39, rocker lever 53 and knock-out lever 41 areessentially rigid and the equivalent of a single lever, but with nobacklash. When the lever 41 is initially set against plunger 60 andlever 39 is aligned therewith the end point of the stroke of lever 41 isestablished and during cyclic operation of the lever system,

lever 41 always terminates its knock-out stroke at this set point.

The foregoing adjustment is applicable to the machine as illustrated. Onmultiple station heading machines, the drive lever 39 could be actuatedby rotating the shaft to which it is attached.

In this arrangement it may be seen that during the knock-out operationthere is no backlash once the link 30, operated from the knock-out cam,contacts the drive lever 39 since rocker lever 53 simultaneouslycontacts both knock-out lever 41 and drive lever 39, and there is noclearance therebetween. This arrangement maintains the backlash in theoverall knock-out assembly to a minimum which allows higher speeds ofoperation without objectionable noise levels, and minimizes the impactand acceleration loads on the part of the knock-out assembly.

Another embodiment of the invention is shown in FIG. 5 wherein a drivemeans in the form of a cam 70 is utilized to return a positioning lever71 equivalent to the knock-out lever 41 to a retracted position. In thisembodiment of the invention lever 71 normally acts upon a member 72movable in a guide 73 in a frame 74. Lever 71 is pivoted to the frame at75 and a drive lever 76 is pivoted to the frame at one end thereof at77, and at the other end thereof pivotally carries a cam follower 78which is driven by cam 70. Lever 71 is normally urged towards member 72by means of a plunger 79 biased by a spring 80, and moves between theposition shown, determined by an adjustable stop 81, and a positionagainst face 81a. A rocker lever 82 is pivotally mounted to a block 83which may be adjustably positioned in channel 84 on frame 74. Y

The operation of the mechanism shown in FIG. 5 will be apparent from theforegoing description and it need only be pointed out that in thisarrangement the cam 70 retracts lever 71 from the positionable member 72against the bias of spring 80. The initial adjustment of the mechanismof FIG. 5 is similar to that previously described, the primarydifference in the mechanisms of FIGS.l-4 and FIG. 5 being that the drivestroke in one instance in used to advance the positioning lever while inthe other instance it is utilized to retract the positioning lever.

It will further be noted that the adjustable rocker lever in both casesacts as a variable force multiplier dependent upon its position relativeto the drive and positioning levers.

It may thus be seen that the objects of the invention set forth as wellas those made apparent from the preceding description are efficientlyattained. While a preferred embodiment of the invention has been setforth for purposes of disclosure other embodiments of the invention aswell as modifications to the disclosed embodiment thereof which do notdepart from the spirit and scope of the invention may occur to thoseskilled in the art. Accordingly, the appended claims are intended tocover all embodiments and modifications to the disclosed embodiment ofthe invention which do not depart from the spirit and scope thereof.

We claim:

1. In a forming machine having a frame member, a die adapted to receivea workpiece for forming, a pin adapted to be inserted into said die toknock out a workpiece therefrom, a punch member adapted to formworkpieces inserted in the die, a drive mechanism for reciprocating thepunch toward and away from the die, cam means driven in timed relationto the punch and connecting means reciprocally driven by the cam means;a knockout pin operating assembly comprising first and second levers,said first and second levers having adjacent ends pivotally mounted tosaid frame member, said first lever being arranged to advance the pininto the die, said second lever being arranged to be pivoted by theconnecting means, a third lever pivotally mounted to the frameintermediate the ends thereof, said third lever being in contactadjacent the ends thereof with said first lever and said second lever sothat upon pivotal motion of said second lever by the connecting meanssaid third lever moves said first lever to advance said pin.

2. The invention of claim 1 wherein the pivotal mounting of said thirdlever is movable on said frame to adjust its points of contact with saidfirst lever and said second lever.

3. The invention of claim v1 further including a member slidably mountedto the frame, said third lever being pivotally mounted to said member.

4. The invention of claim 3 including guide means carried on said frame,said member being movably mounted on said guide means.

5. The invention of claim 4 wherein said guide means includes a threadedshaft, said member threadedly receiving said shaft and non-rotatablymounted to said guide means so that upon rotation of said shaft saidmember moves longitudinally along said shaft.

6. The invention of claim 1 further including means biasing said firstlever toward said third lever.

7. The invention of claim 1 wherein said first lever and said secondlever are pivotal with respect to a common axis.

8. A mechanism for knocking a workpiece from a die comprising a pinadapted to be inserted in the die, a frame member, first and secondlevers, said first and second levers having adjacent ends pivotallymounted to said frame member said first lever being arranged to advancesaid pin into the die, drive means for pivoting said second lever and athird lever pivotally mounted to the frame, said third lever being incontact at opposite ends thereof with said first lever and said secondlever so that upon pivotal motion of said second lever said third levermoves said first lever to advance said pin.

9. The mechanism of claim 8 further including means for adjusting theposition of said third lever with respect to said first lever and said'second lever.

10. The mechanism of claim 9 wherein said first lever and said secondlever are pivotally mounted about a common axis and said third levercontacts said other levers on opposite sides of said axis.

11. An apparatus for controlling the position of a member in a definedguide means comprising a frame member, first and second levers, saidfirst lever being pivoted to said frame member at one end thereof, theother end of said first lever adapted to operate on said member, biasingmeans acting upon said first lever intermediate the ends thereof andarranged to pivot said first lever in a first direction, a second leverpivotally mounted to said frame member at one end thereof adjacent thepivoted end of said first lever, a third lever pivotally mountedintermediate the ends thereof to said frame and having its ends bearingon said first and second levers, and drive means for acting on the freeend of said second lever to move said second lever about its pivot pointand cause said third lever to produce pivotal motion of said first leveragainst the force of said biasing means.

12. The apparatus of claim 11 wherein said first and second levers havea common pivotal axis.

13. The apparatus of claim 11 wherein the third lever is movable on saidframe to adjust its points of contact on said first and second levers.

14. A variable stroke positioning apparatus with accurate repeatabilityto a fixed endpoint comprising a rigid member, a first lever pivoted atone end to said rigid member, the other end of said first lever adaptedto operate on a point whose spatial relationship to said rigid member isfixed, a second lever pivotally mounted at one end to said rigid memberadjacent the pivoted end of said first lever, a third lever pivotallymounted at a point intermediate its ends with respect to said rigidmember, said third lever being spaced in relationship to said first andsecond levers so that the ends of said third lever bear against saidfirst and second levers, and drive means for acting on the other end ofsaid second lever to move said second lever about its pivot point andcause said third lever to produce pivotal motion of said first levertoward said fixed point.

15. The apparatus of claim 14 wherein said first and second levers havea common pivotal axis.

16. The apparatus of claim 14 wherein said third levers pivot point withrespect to said rigid member is adjustable so as to vary the stroke ofsaid first lever.

17. The apparatus of claim 14 wherein said first lever is biased in adirection away from said fixed point.

References Cited UNITED STATES PATENTS 3,112,660 12/1963 Hoyt 10-12 XCarlson l0ll X Carlson l0l1 X Maistros 72427 X Hoyt 1011 X Nebendorf72427 X McClellan 1025 X Van De Meerendonk 72427 X CHARLES W. LANHAM,Primary Examiner.

US. Cl. X.R.

